The Netherlands, with its permissive marijuana laws, may be known as the cannabis capital of the world. But a survey published this month in PLoS Medicine, a journal of the Public Library of Science, suggests that the Dutch don't actually experiment with pot as much as one would expect. Despite tougher drug policies in the U.S., Americans were twice as likely to have tried marijuana than the Dutch, according to the survey. In fact, Americans were more likely to have tried marijuana or cocaine than people in any of the 16 other countries, including France, Spain, South Africa, Mexico and Colombia, that the survey covered.

Researchers found that 42% of people surveyed in the U.S. had tried marijuana at least once, and 16% had tried cocaine. About 20% of residents surveyed in the Netherlands, by contrast, reported having tried pot; in Asian countries, such as Japan and China, marijuana use was virtually "non-existent," the study found. New Zealand was the only other country to claim roughly the same percentage of pot smokers as the U.S., but no other nation came close to the proportion of Americans who reported trying cocaine.

Why the high numbers? Jim Anthony, chair of the department of epidemiology at Michigan State University and an author of the study, says U.S. drug habits have to do, in part, with the country's affluence  many Americans can afford to spend their income on recreational drugs. Another factor may be an increasing awareness that marijuana may be less toxic than other drugs, such as tobacco or alcohol. (However, the study also found that the U.S. is among the leading countries in the percentage of respondents who have tried tobacco and alcohol). As for the popularity of cocaine, the reason may simply be the close proximity of South America, the world's only coca plant producer. And finally, Anthony notes, it's a matter of culture: the U.S. is home to a huge baby boomer population that came of age when experimenting with drugs was a part of the social fabric. "It became a more mass-population phenomenon during a period when there were a large number of young people who were in the process of creating a culture of their own," Anthony says.

The survey also found that more Americans not only experimented with drugs, but also tended to try pot and cocaine for the first time at a younger age compared with people in other countries. Just over 20% of Americans reported trying pot by age 15 and nearly 3% had tried cocaine by the same age. Those percentages jumped to 54% and 16%, respectively, by age 21. That finding isn't surprising, says Dr. Richard Schottenfeld, a professor of psychiatry and a drug expert at the Yale University School of Medicine, since peer influence has a significant impact on the prevalence of drug use. In the Netherlands, for example, there is a large, vocal and homogeneous conservative population that is staunchly opposed to marijuana, says Schottenfeld. And anti-drug activists have made recent attempts to tighten the country's cannabis policies.

Yet experts say the findings of the new survey don't fairly reflect the success or failure of any particular drug policy. The survey asked only whether people had ever tried drugs in their lifetime  it did not ask about habitual use. "For drug policy, what you look at is regular use," says Tom Riley, a spokesman for the U.S. Office of National Drug Control Policy. "Somebody having tried pot in 1968 in college doesn't really have much to do with what the current drug use picture in the United States is."

Though current findings may not provide enough context to judge existing drug policy, Anthony says they do highlight some valid issues, especially since stringent laws don't appear to impact whether kids experiment with drugs. "One of the questions raised by research of this type is whether Americans will want to continue supporting the incarceration of young people who use small amounts of marijuana," Anthony says.

The ongoing study, which surveyed more than 85,000 people in 17 countries, is part of a larger project through the World Health Organization's World Mental Health Survey Initiative. Anthony says further research about the frequency of worldwide drug use, and new data from additional countries will be released in the future.